the Dead Escapement. 1 7 



the angle O I X, and consequently the point T of the lineTD, 

 or inclined plane of the pallet BB, instead of having advanced a 

 sufficient quantity to meet the tooth 1 at the point G, will only 

 have advanced to H, and the point of the tooth 1 would drop upon 

 the inclined plane H K of the pallet between H and P, and the 

 pallet advancing with less rapidity than the wheel they will meet 

 nearer P than H *. 



In the other case (the center of motion of the pallets is dropped 

 nearer to the center of the wheel) the action of the wheel upon the 

 inclined plane of the pallet A A, Fig. 3, Plate III, would lead the 

 pendulum, an angle exceeding the angle OIQ of lead already 

 drawn, by a quantity equal to the angle I O X, and consequently 

 the pallet BB will be led so much too deep into the wheel, that the 

 point of the tooth 1 instead of dropping safely upon the pallet, 

 will drop upon its circular rest at a very considerable distance 

 from the point H f. 



It would be impossible for any clock to go with the pallets 

 shaped, as drawn Fig. 2 and 3, Plate III ; but it does not follow 

 that pallets could not be made, preserving the same centers of mo- 

 tion, which would perform ; and, at first sight, and upon a small 

 scale, appear as mathematically correct as the escapement drawn 

 Fig. 1, Plate III. Such pallets are represented Fig. 2 and 3, Plate 

 IV, applied to similar wheels ; taking over the same number of 

 teeth, and acting on the same centers as in Fig. 2 and 3, Plate III. 

 These pallets will be led an equal angle by the action of the 

 wheel on each pallet, and lead the pendulum an angle equal to the 

 angle it is led with the center of action of the pallets in its proper 

 place, as in Fig. 1, Plate III. 



* The effect that would result in practice from the tooth dropping on the 

 inclined plane of the pallet, would be to cause the scape wheel, and conse- 

 quently the whole train of wheels, to recoil ; an evil subversive of the prin- 

 ciple of the escapement. 



t The effect produced by the tooth taking more hold on the circular rest 

 than is absolutely necessary for safety, is to considerably increase the friction 

 ou the rest. In practice the tooth should drop just on the circular rest, and 

 no more. 



Vol. XVI. C 



